I have not yet played either game, but I have personally been waiting for 'The Kings' to come back into the AppStore so I could purchase it. I plan on doing that tonight. From what I understand, both games are from the same developer, but 'The Kings' came out after and seems to have better reviews and a better gaming experience.
The dev fixed a lot of the grammatical issues I had in The Kings, and the game has a ton of content. It has a lot the micromanagement that I like with this type of game, and also has a Uniwar flavor to it in the battles. War Generation is strictly like Uniwar and doesn't have much depth besides the different maps. My suggestion is you go with The Kings.
Bad engrish worse gameplay pretty graphics glad I waited till $1 id have been Pissed about $5 1 star bad and I LOVE turn based strategy